Active solubilization and refolding of stable protein aggregates by cooperative unfolding action of individual Hsp70 chaperones

Anat Ben-Zvi, Paolo De Los Rios, Giovanni Dietler, Pierre Goloubinoff*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

Hsp70 is a central molecular chaperone that passively prevents protein aggregation and uses the energy of ATP hydrolysis to solubilize, translocate, and mediate the proper refolding of proteins in the cell. Yet, the molecular mechanism by which the active Hsp70 chaperone functions are achieved remains unclear. Here, we show that the bacterial Hsp70 (DnaK) can actively unfold misfolded structures in aggregated polypeptides, leading to gradual disaggregation. We found that the specific unfolding and disaggregation activities of individual DnaK molecules were optimal for large aggregates but dramatically decreased for small aggregates. The active unfolding of the smallest aggregates, leading to proper global refolding, required the cooperative action of several DnaK molecules per misfolded polypeptide. This finding suggests that the unique ATP-fueled locking/unlocking mechanism of the Hsp70 chaperones can recruit random chaperone motions to locally unfold misfolded structures and gradually disentangle stable aggregates into refoldable proteins.

Original languageEnglish
Pages (from-to)37298-37303
Number of pages6
JournalJournal of Biological Chemistry
Volume279
Issue number36
DOIs
StatePublished - 3 Sep 2004
Externally publishedYes

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